Heave compensation for vessels and/or their loads can be critical for offshore lifting and landing operations. This is because it may be desirable for a vessel subject to wave action to maintain the load in a fixed location and/or at a constant tension. Heave compensation systems may operate in a variety of ways including via active heave compensation modes where the system controls the position of the load, passive heave compensation modes where the system controls the tension on the load, and combinations of both active and passive heave compensation modes.
A winch-based heave compensation system may operate in both a passive and active mode, may be part of a main winch that controls the line supporting a load, and may include a number of sheaves that the line passes over as the winch undergoes a spooling movement. One disadvantage of some heave compensation systems is that the line moves over or flexes at one or more (often multiple) elements in the compensation system and may be damaged or fail due to fatigue caused by the line continuously bending back-and-forth over the elements (by travel or flexing without line travel) when the heave compensation system is operating. This problem is particularly present with lighter-weight lines made from fiber materials other than steel. Therefore, there is a need for a heave compensation system that operates to reduce the amount of fatigue on the line in order to prevent line damage or failure.